Prof. Wen-Jun WANG's Group

Rapid collection and re-dispersion of MOF particles by a simple

and versatile method using a thermo-responsive polyme

In conclusions, an easy but versatile method for fast collection and re-dispersion of MOF particles in water has been developed and demonstrated. It is through simple addition of small amount thermal-responsive poly(N-isopropylacrylamide), that is, PNIPAM, to MOF particle suspension. Some added PNIPAM chains are adsorbed onto the surface of MOF particles, while other chains are free in the solution. The adsorbed chains improve the stability of MOF particles in water below LCST. The free chains interact with adsorbed chains when the temperature is elevated above LCST, leading to the formation of large MOF-PNIPAM aggregates, which can be easily collected. Compared to grafting smart polymers, this method does not involve any chemical reactions. It imposes little risk to damaging MOF structures and properties. It can also be applied to various MOF–water systems. A model application was performed using MIL-100(Fe) as photocatalyst to decolorize MB in water. The MOF catalyst can be quickly collected by adding free PNIPAM at 40 °C and reclaimed and reused for three times without any catalytic activity loss. This method paves a way for fast dispersion and recovery of nano to micro-sized particulate materials, which is very useful in catalyst and separation applications.

RSC Advances, 2016, 6(68): 63398-63402.